Orm Curry was Aquaman's fully human half-brother, the son of Tom Curry (Aquaman's father) and a woman named Mary O'Sullivan. He grew up under the shadow of his heroic half-brother and resented the fact that he had none of Aquaman's powers, being fully human, and he was already a petty criminal when he was stricken with amnesia and forgot all about his former life, disappearing shortly afterwards.

Several years later, the self-named Orm Marius reappeared as the Ocean Master, a high-tech pirate who initially attacked ships but quickly moved on to causing natural disasters in order to hold the world at ransom. Aquaman and Aqualad were captured by Ocean Master but managed to escape. Aquaman was then unable to fight Ocean Master after having seen behind the Ocean Master's mask and realizing that he was his half-brother Orm, although he did stop his plan.

In his subsequent appearances Ocean Master, believing Aquaman was afraid of him, had decided to overthrow Aquaman and usurp his throne. Unable to survive underwater, he made a special costume and helmet to help him breathe while in the ocean and clashed with Aquaman many times. Ocean Master regained his memory when Deadman took possession of his body and unlocked Orm's memories in Aquaman #50 (March–April 1970), but he continued to plot against his half-brother.

The Ocean Master's origins changed following Peter David's reinvention of Aquaman. He is still Aquaman's half-brother, but since Aquaman is no longer the son of Thomas Curry, Orm is now the son of Atlan the wizard (Aquaman's true father) and an Inupiat woman.

He first appeared in #3 of the miniseries Aquaman: Time and Tide (February 1994), in which Aquaman recorded the story of his life. This told how one of his early encounters with humans was when he rescued a girl named Kako from a polar bear. Her family were all traditionalists, except her cousin Orm, who had no time for the old ways. When Kako and Arthur began a sexual relationship Orm attacked her in a jealous rage. Although she survived, she did not recall what had happened to her.

Orm appeared in his Ocean Master costume in the next issue, which is set early in Orin's career as Aquaman and his rule of Atlantis. As in pre-Crisis continuity, Ocean Master desires the throne of Atlantis, having learnt his father was an Atlantean wizard. At this time neither he nor Aquaman knew of their relationship, although Aquaman would make the connection while recording the events.

During the Underworld Unleashed storyline, Ocean Master later started using mystical powers when sold his soul to Neron for a powerful trident which gave him great power, but caused agony if released. With this, he conquered the Dreaming City, a nation of Atlantean offshoots. He has been found by Aquaman, who was seeking to unite all the tribes of Atlantis. Aquaman convinced Ocean Master that they were half-brothers, however the pressure of this caused Orm's mind to snap.

Following this he briefly joined Lex Luthor's Injustice Gang, an "all archenemies" counterpart to the "Big Seven" Justice League. He also attempted to aggravate the tensions between Atlantis and the surface country of Cerdia.

Ocean Master clashed with the JLA again when he attempted to claim the remains of Atlantis following Aquaman's apparent death in Our Worlds At War.

Orm was last seen having used his mystical talents to alter reality so that he was Aquaman and Orin was Ocean Master. As Aquaman, Orm held Sub Diego under his evil rule. However the heroic Ocean Master was able to defeat him.

In The New 52 (the 2011 relaunch and retcon of DC Comics' entire series), Ocean Master's origins are once again revised. According to the Atlantean advisor Vulko, the queen of Atlantis, Atlanna left her first child, Arthur Curry, to live with his father on the surface world, thus protecting him from the effects of Atlantean tyranny. Atlanna is later forced to marry a member of the Atlantean Guard and gives birth to her second child, Orm. Twelve years later, Orm's father is killed and Atlanna dies under unknown circumstances, making Orm the new king. Vulko accuses Orm of killing Atlanna, but fails to produce evidence and flees. When Vulko is later confronted by Arthur (who is searching for Atlantis), he explains his brother's origins and tells him that Arthur is the rightful heir of Atlantis's throne, and therefore, must overthrow Orm.[1]

Ocean Master is eventually contacted by Aquaman, who suspected Orm to be the Atlantean hiring Black Manta to steal the relic scepter, an Atlantean object of power from the Dead King's tomb.[2] When the Atlantean retrieves the relic, Aquaman believes Ocean Master is in the Atlantean ship and demands that he reveal himself, but the Atlantean ship escapes.[3] Later, Ocean Master is visited by Aquaman to ask if he took the scepter, but Ocean Master claims that he did not, saying that if he wanted the relic scepter he would ask Aquaman for it.[4] It is also revealed that Aquaman allowed Ocean Master to maintain the throne with the promise that he would not invade the surface world.

During the Throne of Atlantis storyline, someone sabotages an aircraft carrier and provokes it into attacking Atlantis. Believing to be under attack from the surface, Ocean Master leads Atlantean soldiers to invade the carrier and then wage war on the surface.[5] Ocean Master arrives in Boston, attacking seafarers and asking for his brother, Aquaman. Aquaman confronts and attempts to talk sense to him, but they are interrupted by the Justice League without warning. Aquaman defends his brother, refusing to have him face extradition.[6] Attacked on multiple fronts, Ocean Master electrocutes then imprisons the Justice League within water cocoons. He sends the Justice League to the abyssal plain, while he attempts to sink the city of Boston.[7]

While Ocean Master and his Atlantean soldiers use bomb detonators to sink the city and face off against the superheroes that Cyborg called in as reserves, they are attacked by sea creatures known as the Trench. After the Justice League escape from the abyssal plain, Aquaman realizes Ocean Master is not using the relic scepter to sink the city. Since the Trench can only be commanded with the relic scepter, someone else must be using it to manipulate the Atlantean war. The mastermind is revealed to be Vulko.[8]

The Justice League arrive to battle both the Atlanteans and the Trench, while Aquaman attacks his brother and tries to convince him that Vulko is responsible for the Atlantean war. However, Ocean Master refuses to listen, believing that Aquaman has been corrupted by the surface world. The Justice League manage to dispose of all the bomb detonators in Boston, but Ocean Master tries to use his control helmet to summon a tidal wave. Mera's power turns the wave to hard water to stop it. Ocean Master is defeated by Aquaman, who reclaims the throne and takes command of the deceived Atlantean soldiers. The Trench are returned home and Vulko is taken in for an Atlantean trial. However, Ocean Master is remanded to Belle Reve for his crimes after abdicating the throne and losing political immunity in the process. As he is taken away, Aquaman apologizes to Ocean Master.[9]

Afterwards, the renegade Atlantean, Murk, makes plans to break Ocean Master out from his surface world prison.[10] While in Belle Reve, Ocean Master is advised by his lawyer that he must plead guilty to the criminal charges against him.[11] Murk and other Atlanteans arrive to free Ocean Master in Belle Reve, but they are intervened by a message that Atlantis is under attack. Murk and the Atlanteans do not know what to do with their choices and decide to return.[12]

During the Forever Evil storyline, the lawyer is unable to convince Ocean Master to no avail when Deathstorm and Power Ring invade Belle Reve killing his lawyer. During Belle Reve's prison break, Ocean Master walks out to reclaim his Atlantean throne clothes when a critically wounded prison officer begs for help; after noticing that the officer was actually the only prison Guard who was nice to him, Ocean Master "saves" him by mercy killing him. Ocean Master then runs into fellow escapees who are attacking a small-town diner, and whilst he is initially not bothered about confronting them, once they turn their attentions to him, he takes them out. A woman who was in the diner desperately wants him to save her young son, but Ocean Master refuses, instead heading back to the ocean. However, he changes his mind, going back mid-way through his path to save him.[13] In the aftermath of the attack, Ocean Master has started to live with the woman and her child, entertaining the latter with stories from his time in Atlantis. Suddenly, Orm is confronted by the king of Xebel, Nereus, who offers him the opportunity to join him to allow the kings of the Seven Seas to rule Earth once more.[14]

Ocean Master is a master of magical manipulation and can utilise it for many effects including magical bolts and telepathy.

After making a deal with the demon Neron, Ocean Master can now manipulate even larger amounts of magical energy. The price of this however is a horribly scarred face and he was given a trident as a focus for his power. If Ocean Master is separated from the trident, he suffers excruciating pain. He also wears a helmet that lets him breathe underwater and special body armor that lets him withstand the pressures of deep water and offers some resistance to physical attacks.

In the New 52 reboot, he has been seen using a trident that can control lightning (referred to as the storms) and a helmet that allowed him to control massive amounts of water to the effects of tsunami, water spouts and other powerful effects. This helmet (or crown as it was referred to) was broken by Aquaman punching Orm. He fought Aquaman quite equally and seemed capable of breathing under water like any other Atlantean.

In the alternate timeline of the Flashpoint event, Ocean Master aids his brother Aquaman in attacking the pirate Deathstroke.[15] After they take them out, Ocean Master attempts to kill the leader Deathstroke, but is then stopped by his brother, Aquaman, who forces them to leave as he had other work to do.[16] Unbeknownst to Aquaman, it was also revealed that Orm was one of those responsible for the war between the Atlanteans and Amazons, as he had joined forces with Artemis and Hippolyta's sister, Penthesileia to prevent the union of the two civilizations. The plot ended with the death of Hippolyta, Diana's mother, who took Artemis's strike (meant for Diana) on the wedding day.[17] Aquaman reassigns Ocean Master and Siren to assassinate Terra in New Themyscira. The mission failed, with Siren being killed by Penthesileia.[18] Ocean Master is later revealed to had been caught by Wonder Woman, after she saw him and her aunt kissing which prompted in her discovery that the war between the Atlanteans and the Amazons was a ruse planned by them. Later, they say they plan to stop each of the opposing powers, meaning they will be thought of as heroes, and they plan to rule the world together.[19]

Orm (not using the names of Ocean Master, Marius or Curry) appeared in an episode of Justice League voiced by Richard Green. In this portrayal, he is a full Atlantean and a member of the royal court. When Orm went to the surface, he hired Deadshot to assassinate Aquaman so he could claim the throne as his own and took action against the surface dwellers by melting the polar ice caps. He was eventually defeated by Aquaman and is presumed dead after plummeting down a ledge. In the Justice League season one DVD box set Bruce Timm said they considered bringing Orm back in costume but scratched the idea because they thought the name "Ocean Master" was too corny as well as having to deal with bringing him back after he had fallen from the cliff in his last appearance.

Ocean Master makes an appearance in the animated series Batman: The Brave and the Bold voiced by Wallace Langham. Here, Aquaman's brother Orm has returned to Atlantis after Aquaman gives him a second chance. After an attempted assassination on Aquaman's life is thwarted by Batman, the Dark Knight is hesitant to believe that Orm has turned over a new leaf. Later on, it is revealed that he is working with Black Manta to steal the throne from Aquaman, and he even succeeds in capturing his brother (donning the mantle of Ocean Master during the process). Black Manta betrays him however, leading to the two putting aside their differences to save Atlantis. Orm is imprisoned in the end, and is forced to listen to tales of heroism from Aquaman (much to Orm's dismay). Despite what happened, Orin gives Orm a second chance (because "they are family").

Ocean-Master (name spelled with a dash) appears in Young Justice voiced by Roger Craig Smith. In "Downtime," it is revealed that Aqualad first came to the attention of Aquaman by helping him in a battle against Ocean Master. The identity of Ocean-Master is not revealed in the episode, but Prince Orm appears later and shows no visible signs of hostility towards his brother (which he held a secret as revealed in the comics). When Black Manta attacks Atlantis, Orm worked to protect Queen Mera. Nonetheless, Ocean-Master later appears in the episode "Revelation" where it is revealed that he is L-5 of "The Light" (Project Cadmus' Board of Directors) who spoke with Black Manta at the end of "Downtime." In "Auld Acquaintance," Ocean-Master appears with Ra's al Ghul, Lex Luthor, Queen Bee, and Brain when they raid Cadmus and steal all the clones. In "Alienated," it is revealed that Ocean-Master was replaced in the Light by Black Manta after having apparently lost his standing due to some undisclosed disgrace.

Ocean Master appears in Justice League: War voiced by an uncredited Steven Blum. He appears in a post-credits scene on an Atlantean ship, holding the body of his king and vowing revenge on the surface world for the deaths of marine wildlife, which he mistakenly believes to have been an unprovoked attack — in reality, it was caused by Darkseid's invasion.

Ocean Master appears as the main antagonist in the Justice League: War sequel, Justice League: Throne of Atlantis, voiced by Sam Witwer.[20] At the beginning of the film, Orm and Black Manta meet with Queen Atlanna (Orm's mother) to convince her to declare war on the surface world for the destruction caused by Darkseid's attack. After she rejects their proposition, Orm tells Black Manta to use missiles (that his men stole from a nuclear submarine earlier) loaded into his submarine to attack Atlantis, framing the surface world. Orm and Black Manta then demand that the Queen launch a war for the alleged act of terrorism from the surface. However, Queen Atlanta still refuses to strike and tells Manta to arrange a meeting with the Justice League to discuss a peace treaty. After his men fail to kill his half brother, Aquaman, Orm kills Queen Atlanta and usurps the throne of Atlantis, once again framing the humans for killing his mother. As King, Orm dons his armor and becomes the supervillain "Ocean Master". When Aquaman and the Justice League arrive at Atlantis to stop him, Ocean Master defeats and captures them, offering them to the Trench. Ocean Master leads his Atlantean army to wage war with the surface, killing many humans in the process. The Justice League manage to free themselves and return to the surface to stop Ocean Master's army. Throughout the battle, Ocean Master easily defeated the entire Justice League until only his half brother remained. As Ocean Master was about to kill Aquaman, Cyborg broadcast a recording of Ocean Master confessing to murdering his own mother. After hearing the truth, the Atlanteans cease their attack as Aquaman knocks Ocean Master out and becomes the new King of Atlantis. In the post-credits scene, Ocean Master is imprisoned in Belle Reve Prison. As Orm demands to speak to Aquaman, Lex Luthor appears and states that he has a proposition for him.

The latest rumors have stated that Karl Urban may play Ocean Master in the upcoming standalone Aquaman movie being developed at Warner Bros. Pictures. [21]

Ocean Master appears in DC Universe Online voiced by Sandy McIlree. He appeared as part of the "Tides of War" Summer event. In the hero campaign, the players are sent by Oracle to assist Aquaman into preventing Ocean Master into taking over an Atlantean outpost near Metropolis. Afterwards, the players must help Aquaman's naval force board and destroy Ocean Masters' mutineer naval forces in the strait of Little Bohemia. In the villain campaign, the players are sent by Calculator to assist Ocean Master in his attempted coup on Aquaman by assisting his forces into taking over an Atlantean outpost near Metropolis. Afterwards, the players help Ocean Master's naval force board and destroy Aquaman's naval forces in the strait of Little Bohemia. Ocean Master's mutineers consist of Mutineers and Mutineer Quartermaster.

Ocean Master is mentioned in Injustice: Gods Among Us. When Aquaman is confronted by the alternate Aquaman in Atlantis, the alternate Aquaman asks Aquaman if he either works for Ocean Master or Black Manta.

Ocean Master appears as a boss in Scribblenauts Unmasked: A DC Comics Adventure. He is seen in the world "Atlantis" and in the final level fighting Aquaman. He can also be seen in Aquaman's origin story. Furthermore, he can be created in the game at almost any point.

In the comic spin-off to Young Justice, Orm's double-life as Ocean-Master was confirmed in issue 14. Ocean Master debriefed his Atlantean Purists into terrorizing the impure Atlanteans while Aquaman is away. Before their attack, Ocean Master allayed their fear of Aqualad and told them to be ready nonetheless. When the Atlantean Purists attacked Atlantis, Ocean-Master had Queen Mera at his mercy.